service for complex look up

nodejs/utils/callback_queue.js

@@ -0,0 +1,26 @@
+'use strict';
+
+class CallbackQueue{
+	constructor(callbacks){
+		this.__callbacks = [];
+
+		for(let callback of Array.isArray(callbacks) ? callbacks : [callbacks]){
+			this.push(callback);
+		}
+	}
+
+	push(callback){
+		if(callback instanceof Function){
+			this.__callbacks.push(callback);
+		}
+	}
+
+	call(){
+		let args = arguments;
+		this.__callbacks.forEach(function(callback){
+			callback(...args);
+		}.bind(this))
+	}
+}
+
+module.exports = {CallbackQueue};